1. Field of the Invention
This invention is generally directed to methods of manufacturing fireworks and particularly to a method of manufacturing fireworks wherein a relatively small Class C firework may be manufactured in a first location to include an explosive powder which is surrounded by a relatively soft paper shell and which is ignitable through the use of an enlarged safety fuse extending axially of the shell. Preferably, the relatively small firework is assembled at a second location, remote from the first location, within a supplemental housing having a width or diameter of at least twice that of the small firecracker. The small firecracker is mounted centrally within the supplemental enclosure and retained therein by a disc adhered to each end thereof with the safety fuse being extended through one of the discs so as to extend exteriorly of the supplemental enclosure.
2. History of the Invention
Over the years there have been numerous developments in the manufacture of fireworks and firecrackers. In more recent times, emphasis has been placed on developing fireworks which can be more safely handled by the consuming public without fear of accidents or injuries. In this regard, the Department of Transportation and the Consumer Product and Safety Commission of the Federal Government have set strict regulations with regard to the construction and handling of fireworks which may be sold to the general public. The Consumer Product and Safety Commission has also made significant inroads into the control and safe use and manufacture of fireworks. Over the past few years, the amount of explosive in fireworks to be sold to the general public has been restricted to a limit of 50 milligrams or approximately 0.772 grains of powder. The increase in safety is substantial when it is considered that the use of fireworks having 10 grains of powder was prevalent just 10 to 20 years ago.
The reduction in the amount of powder permitted by federal authorities has increased the safety factor but, of course, has reduced the noise level which is attainable using conventionally manufactured firecrackers. Most of the legally permitted firecrackers use a paper housing which is approximately 1/4 of an inch in diameter and 1 inch or 11/2 inch in length and which has a paper and powder fuse which extends therefrom. The housing contains no more than 50 milligrams of explosive powder. The problem continues, however, that the use of conventional 1 inch or 11/2 inch Class C fireworks presents a potential safety risk to the user. All too often accidents result from the improper handling of fireworks and thus it is imperative that the fireworks be constructed so as to decrease the potential for accidents and injury even by the careless user.
In an attempt to make fireworks safer, some manufacturers are beginning to place a powder charge within a reinforced or stronger housing having a size and diameter which is significantly greater than the standard 1 inch by 1/4 diameter firework. In U.S. Pat. No. 4,052,940 to Gits et al., a firecracker is disclosed which utilizes a casing of approximately 1 to 13/4 inches in length by 1/2 to 5/8 inches in inside diameter to retain an explosive charge. The explosive charge is retained in a supplemental chamber formed within the housing by capped ends which are inserted and adhered inwardly of the ends of the casing after which a sealant material is applied to the ends and outside of the sealing caps.
One of the purposes achieved by using a larger housing to retain a small explosive charge is to increase the audible characteristics of the firework by balancing the bursting effect of the housing together with the sealing plugs or caps at either end thereof. As disclosed in the above referenced patent, however, the explosive charge is freely disposed within the central portion of the firework, and the fuse is extended directly through the side wall of the casing. Therefore, not only is the charge able to leak through the opening in the sidewall of the housing where the detonating fuse is extended, but as the detonating charge is free to engage the inner sidewall of the housing, such charge may be ignited while in intimate contact with the container walls thereby presenting the possibility of injury in the event the firecracker prematurely explodes in the hands of the user.
Another prior art attempt to create safer small charge fireworks makes use of a housing of generally the same size as that disclosed in the aforementioned patent to Gits et al. In this other prior art structure, the charge is contained within a plastic capsule from which a detonating fuse extends so as to be axially positioned outside the firecracker housing. The ends of the housing are sealed after the chamber surrounding the capsule has been filled with sawdust which initially holds the capsule in place. With this type of construction, the small capsule containing the explosive charge may be agitated or shifted to a position engaging the sidewalls of the firecracker housing. Therefore, this construction presents the same potential risk of the exposive charge being ignited against the sidewall of the firecracker thereby potentially injuring a person who may be handling the firework. Additionally, the sawdust will also have an affect of muffling the retort and thereby reduce the audible level of the salute or firecracker.
A remaining problem which has not been addresed by the prior art is in the handling and manufacturing techniques involved with fireworks. In both the aforementioned prior art fireworks, the total firecracker is assembled at one location where the powder charge is introduced either directly into the firecracker housing or first into a supplemental capsule and thereafter inserted into the firecracker housing. Thus, the manufacture of these prior art fireworks require that the explosive charge be handled at the point of assembly of the completed firecracker.
In addition to the foregoing, there are numerous patents which discuss general methods of constructing and assembling fireworks as well as structures for pyrotechnic devices including fireworks. In U.S. Pat. No. 2,817,294 to Hjellnes, a training device is disclosed wherein an explosive charge is carried within a first container and thereafter placed into a supplemental housing having a elongated end portion which functions as a handle. The pyrotechnic device is designed to act as a training grenade with the explosive charge being carried at one end of the elongated tubular handle or casing. The design and structure of the device is somewhat complicated as it is intended for use as a military training device and not as a firework to be used by the general public.
Other examples of the prior art include Norwegian Pat. No. 96,660; French Pat. No. 650,395; British Pat. No. 745,192; and U.S. Pat. Nos. 511,644 to Nelson; 547,921 to Hunt; 619,177 to Hinton; 675,102 to Nordlinger; 840,242 also to Nordlinger; and 1,253,598 to Hitt.